Allogeneic immunity clears latent virus following allogeneic stem cell transplantation in SIV-infected ART-suppressed macaques.

Allogeneic hematopoietic stem cell transplantation (alloHSCT) from donors lacking C-C chemokine receptor 5 (CCR5Δ32/Δ32) can cure HIV, yet mechanisms remain speculative. To define how alloHSCT mediates HIV cure, we performed MHC-matched alloHSCT in SIV+, anti-retroviral therapy (ART)-suppressed Mauritian cynomolgus macaques (MCMs) and demonstrated that allogeneic immunity was the major driver of reservoir clearance, occurring first in peripheral blood, then peripheral lymph nodes, and finally in mesenteric lymph nodes draining the gastrointestinal tract. While allogeneic immunity could extirpate the latent viral reservoir and did so in two alloHSCT-recipient MCMs that remained aviremic >2.5 years after stopping ART, in other cases, it was insufficient without protection of engrafting cells afforded by CCR5-deficiency, as CCR5-tropic virus spread to donor CD4+ T cells despite full ART suppression. These data demonstrate the individual contributions of allogeneic immunity and CCR5 deficiency to HIV cure and support defining targets of alloimmunity for curative strategies independent of HSCT.

Correction: Mitigation of endemic GI-tract pathogen-mediated inflammation through development of multimodal treatment regimen and its impact on SIV acquisition in rhesus macaques.

[This corrects the article DOI: 10.1371/journal.ppat.1009565.].

Mitigation of endemic GI-tract pathogen-mediated inflammation through development of multimodal treatment regimen and its impact on SIV acquisition in rhesus macaques.

Here, we assessed the efficacy of a short-course multimodal therapy (enrofloxacin, azithromycin, fenbendazole, and paromomycin) to eliminate common macaque endemic pathogens (EPs) and evaluated its impact on gastrointestinal (GI) microbiota, mucosal integrity, and local and systemic inflammation in sixteen clinically healthy macaques. Treatment combined with expanded practices resulted in successful maintenance of rhesus macaques (RM) free of common EPs, with no evidence of overt microbiota diversity loss or dysbiosis and instead resulted in a more defined luminal microbiota across study subjects. Creation of a GI pathogen free (GPF) status resulted in improved colonic mucosal barrier function (histologically, reduced colonic MPO+, and reduced pan-bacterial 16s rRNA in the MLN), reduced local and systemic innate and adaptive inflammation with reduction of colonic Mx1 and pSTAT1, decreased intermediate (CD14+CD16+) and non-classical monocytes (CD14-CD16+), reduced populations of peripheral dendritic cells, Ki-67+ and CD38+ CD4+ T cells, Ki-67+IgG+, and Ki-67+IgD+ B cells indicating lower levels of background inflammation in the distal descending colon, draining mesenteric lymph nodes, and systemically in peripheral blood, spleen, and axillary lymph nodes. A more controlled rate of viral acquisition resulted when untreated and treated macaques were challenged by low dose intrarectal SIVmac239x, with an ~100 fold increase in dose required to infect 50% (AID50) of the animals receiving treatment compared to untreated controls. Reduction in and increased consistency of number of transmitted founder variants resulting from challenge seen in the proof of concept study directly correlated with post-treatment GPF animal's improved barrier function and reduction of key target cell populations (Ki-67+ CD4+T cells) at the site of viral acquisition in the follow up study. These data demonstrate that a therapeutic and operational strategy can successfully eliminate varying background levels of EPs and their associated aberrant immunomodulatory effects within a captive macaque cohort, leading to a more consistent, better defined and reproducible research model.

A neonatal nonhuman primate model of gestational Zika virus infection with evidence of microencephaly, seizures and cardiomyopathy.

Zika virus infection during pregnancy is associated with miscarriage and with a broad spectrum of fetal and neonatal developmental abnormalities collectively known as congenital Zika syndrome (CZS). Symptomology of CZS includes malformations of the brain and skull, neurodevelopmental delay, seizures, joint contractures, hearing loss and visual impairment. Previous studies of Zika virus in pregnant rhesus macaques (Macaca mulatta) have described injury to the developing fetus and pregnancy loss, but neonatal outcomes following fetal Zika virus exposure have yet to be characterized in nonhuman primates. Herein we describe the presentation of rhesus macaque neonates with a spectrum of clinical outcomes, including one infant with CZS-like symptoms including cardiomyopathy, motor delay and seizure activity following maternal infection with Zika virus during the first trimester of pregnancy. Further characterization of this neonatal nonhuman primate model of gestational Zika virus infection will provide opportunities to evaluate the efficacy of pre- and postnatal therapeutics for gestational Zika virus infection and CZS.

Viral opportunistic infections in Mauritian cynomolgus macaques undergoing allogeneic stem cell transplantation mirror human transplant infectious disease complications.

Allogeneic hematopoietic stem cell transplantation (HSCT) and xenotransplantation are accompanied by viral reactivations and virus-associated complications resulting from immune deficiency. Here, in a Mauritian cynomolgus macaque model of fully MHC-matched allogeneic HSCT, we report reactivations of cynomolgus polyomavirus, lymphocryptovirus, and cytomegalovirus, macaque viruses analogous to HSCT-associated human counterparts BK virus, Epstein-Barr virus, and human cytomegalovirus. Viral replication in recipient macaques resulted in characteristic disease manifestations observed in HSCT patients, such as polyomavirus-associated hemorrhagic cystitis and tubulointerstitial nephritis or lymphocryptovirus-associated post-transplant lymphoproliferative disorder. However, in most cases, the reconstituted immune system, alone or in combination with short-term pharmacological intervention, exerted control over viral replication, suggesting engraftment of functional donor-derived immunity. Indeed, the donor-derived reconstituted immune systems of two long-term engrafted HSCT recipient macaques responded to live attenuated yellow fever 17D vaccine (YFV 17D) indistinguishably from untransplanted controls, mounting 17D-targeted neutralizing antibody responses and clearing YFV 17D within 14 days. Together, these data demonstrate that this macaque model of allogeneic HSCT recapitulates clinical situations of opportunistic viral infections in transplant patients and provides a pre-clinical model to test novel prophylactic and therapeutic modalities.

Behavioral predictors of pairing success in rhesus macaques (Macaca mulatta).

Pair housing is one of the most important components of behavioral management for caged macaques; however, it can result in aggression and injury if partners are incompatible. Knowing when to proceed and when to stop social introductions can be challenging, and can have consequences for the partners. We examined whether behavior early in social introductions predicted success (i.e., partners remained cohoused with full contact for at least 28 days) in 724 female-female and 477 male-male rhesus macaque pairs. We took cage side one-zero focal observations on pairs during the first 2 days of full contact, recording social and aggressive behaviors. The majority of pairs (79.6% of female and 83.0% of male) were successful. The most common behaviors exhibited by pairs during these observations were maintaining proximity, tandem threats, and anxiety. Mounting was also relatively common in male pairs. Grooming and close social contact (e.g., touching) were not common in our study. Several behaviors observed on Day 1 significantly predicted pairing success. For females, these included proximity, tandem threat, rump present, mount, and groom. Day 1 predictors of success for male pairs included proximity, tandem threat, rump present, mount, and social contact. Fewer behaviors predicted success on Day 2. Maintaining proximity on Day 2 predicted success for both sexes, but tandem threat predicted success only for females. Behaviors that predicted incompatibility for females on Day 1 included displace, grimace, threat, bite, and other aggressive contacts. Day 1 predictors of separation for male pairs were displaced, grimace, and abnormal behavior. The only Day 2 behavior that correlated with incompatibility was grimace, which was predictive for males. Interestingly, aggression did not predict incompatibility for male pairs. Identifying behaviors exhibited by monkeys early in the pair introduction that are predictive of long-term compatibility can shape pairing decisions, reducing later stress and potential injury.

Gammaherpesvirus infection and malignant disease in rhesus macaques experimentally infected with SIV or SHIV.

Human gammaherpesviruses are associated with malignancies in HIV infected individuals; in macaques used in non-human primate models of HIV infection, gammaherpesvirus infections also occur. Limited data on prevalence and tumorigenicity of macaque gammaherpesviruses, mostly cross-sectional analyses of small series, are available. We comprehensively examine all three-rhesus macaque gammaherpesviruses -Rhesus rhadinovirus (RRV), Rhesus Lymphocryptovirus (RLCV) and Retroperitoneal Fibromatosis Herpesvirus (RFHV) in macaques experimentally infected with Simian Immunodeficiency Virus or Simian Human Immunodeficiency Virus (SIV/SHIV) in studies spanning 15 years at the AIDS and Cancer Virus Program of the Frederick National Laboratory for Cancer Research. We evaluated 18 animals with malignancies (16 lymphomas, one fibrosarcoma and one carcinoma) and 32 controls. We developed real time quantitative PCR assays for each gammaherpesvirus DNA viral load (VL) in malignant and non-tumor tissues; we also characterized the tumors using immunohistochemistry and in situ hybridization. Furthermore, we retrospectively quantified gammaherpesvirus DNA VL and SIV/SHIV RNA VL in longitudinally-collected PBMCs and plasma, respectively. One or more gammaherpesviruses were detected in 17 tumors; generally, one was predominant, and the relevant DNA VL in the tumor was very high compared to surrounding tissues. RLCV was predominant in tumors resembling diffuse large B cell lymphomas; in a Burkitt-like lymphoma, RRV was predominant; and in the fibrosarcoma, RFHV was predominant. Median RRV and RLCV PBMC DNA VL were significantly higher in cases than controls; SIV/SHIV VL and RLCV VL were independently associated with cancer. Local regressions showed that longitudinal VL patterns in cases and controls, from SIV infection to necropsy, differed for each gammaherpesvirus: while RFHV VL increased only slightly in all animals, RLCV and RRV VL increased significantly and continued to increase steeply in cases; in controls, VL flattened. In conclusion, the data suggest that gammaherpesviruses may play a significant role in tumorogenesis in macaques infected with immunodeficiency viruses.

Miscarriage and stillbirth following maternal Zika virus infection in nonhuman primates.

Zika virus (ZIKV) infection is associated with congenital defects and pregnancy loss. Here, we found that 26% of nonhuman primates infected with Asian/American ZIKV in early gestation experienced fetal demise later in pregnancy despite showing few clinical signs of infection. Pregnancy loss due to asymptomatic ZIKV infection may therefore be a common but under-recognized adverse outcome related to maternal ZIKV infection.

Zika virus infection in pregnant rhesus macaques causes placental dysfunction and immunopathology.

Zika virus (ZIKV) infection during pregnancy leads to an increased risk of fetal growth restriction and fetal central nervous system malformations, which are outcomes broadly referred to as the Congenital Zika Syndrome (CZS). Here we infect pregnant rhesus macaques and investigate the impact of persistent ZIKV infection on uteroplacental pathology, blood flow, and fetal growth and development. Despite seemingly normal fetal growth and persistent fetal-placenta-maternal infection, advanced non-invasive in vivo imaging studies reveal dramatic effects on placental oxygen reserve accompanied by significantly decreased oxygen permeability of the placental villi. The observation of abnormal oxygen transport within the placenta appears to be a consequence of uterine vasculitis and placental villous damage in ZIKV cases. In addition, we demonstrate a robust maternal-placental-fetal inflammatory response following ZIKV infection. This animal model reveals a potential relationship between ZIKV infection and uteroplacental pathology that appears to affect oxygen delivery to the fetus during development.

Nonreducible Inguinal Hernia Containing the Uterus and Bilateral Adnexa in a Rhesus Macaque (Macaca mulatta).

Inguinal herniation of abdominal viscera is a relatively common condition in both humans and domestic animal species. In captive rhesus macaques (Macaca mulatta), the highest incidence occurs in overweight, aged males. However, inguinal herniation of the uterus with bilateral adnexa is extremely rare in both human and veterinary medicine. Here we report a previously undescribed uterine inguinal herniation with bilateral adnexa in a 3-y-old female rhesus macaque. Although uterine herniation remains a rare condition in rhesus macaques, it should be considered as a differential diagnosis in animals with unilateral subcutaneous enlargements in the inguinal region.

Allogeneic stem cell transplantation in fully MHC-matched Mauritian cynomolgus macaques recapitulates diverse human clinical outcomes.

Allogeneic hematopoietic stem cell transplantation (HSCT) is a critically important therapy for hematological malignancies, inborn errors of metabolism, and immunodeficiency disorders, yet complications such as graft-vs.-host disease (GvHD) limit survival. Development of anti-GvHD therapies that do not adversely affect susceptibility to infection or graft-vs.-tumor immunity are hampered by the lack of a physiologically relevant, preclinical model of allogeneic HSCT. Here we show a spectrum of diverse clinical HSCT outcomes including primary and secondary graft failure, lethal GvHD, and stable, disease-free full donor engraftment using reduced intensity conditioning and mobilized peripheral blood HSCT in unrelated, fully MHC-matched Mauritian-origin cynomolgus macaques. Anti-GvHD prophylaxis of tacrolimus, post-transplant cyclophosphamide, and CD28 blockade induces multi-lineage, full donor chimerism and recipient-specific tolerance while maintaining pathogen-specific immunity. These results establish a new preclinical allogeneic HSCT model for evaluation of GvHD prophylaxis and next-generation HSCT-mediated therapies for solid organ tolerance, cure of non-malignant hematological disease, and HIV reservoir clearance.

Correction: Zika Virus infection of rhesus macaques leads to viral persistence in multiple tissues.

[This corrects the article DOI: 10.1371/journal.ppat.1006219.].

Zika Virus infection of rhesus macaques leads to viral persistence in multiple tissues.

Zika virus (ZIKV), an emerging flavivirus, has recently spread explosively through the Western hemisphere. In addition to symptoms including fever, rash, arthralgia, and conjunctivitis, ZIKV infection of pregnant women can cause microcephaly and other developmental abnormalities in the fetus. We report herein the results of ZIKV infection of adult rhesus macaques. Following subcutaneous infection, animals developed transient plasma viremia and viruria from 1-7 days post infection (dpi) that was accompanied by the development of a rash, fever and conjunctivitis. Animals produced a robust adaptive immune response to ZIKV, although systemic cytokine response was minimal. At 7 dpi, virus was detected in peripheral nervous tissue, multiple lymphoid tissues, joints, and the uterus of the necropsied animals. Notably, viral RNA persisted in neuronal, lymphoid and joint/muscle tissues and the male and female reproductive tissues through 28 to 35 dpi. The tropism and persistence of ZIKV in the peripheral nerves and reproductive tract may provide a mechanism of subsequent neuropathogenesis and sexual transmission.

Minimally Invasive Lumbar Port System for the Collection of Cerebrospinal Fluid from Rhesus Macaques (Macaca mulatta).

Biomedical translational research frequently incorporates collection of CSF from NHP, because CSF drug levels are used as a surrogate for CNS tissue penetration in pharmacokinetic and dynamic studies. Surgical placement of a CNS ventricular catheter reservoir for CSF collection is an intensive model to create and maintain and thus may not be feasible or practical for short-term studies. Furthermore, previous NHP lumbar port models require laminectomy for catheter placement. The new model uses a minimally invasive technique for percutaneous placement of a lumbar catheter to create a closed, subcutaneous system for effective, repeated CSF sample collection. None of the rhesus macaques (Macaca mulatta; n = 10) implanted with our minimally invasive lumbar port (MILP) system experienced neurologic deficits, postoperative infection of the surgical site, or skin erosion around the port throughout the 21.7-mo study. Functional MILP systems were maintained in 70% of the macaques, with multiple, high-quality, 0.5- to 1.0-mL samples of CSF collected for an average of 3 mo by using aspiration or gravitational flow. Among these macaques, 57% had continuous functionality for a mean of 19.2 mo; 50% of the cohort required surgical repair for port repositioning and replacement during the study. The MILP was unsuccessful in 2 macaques, at an average of 9.5 d after surgery. Nonpatency in these animals was attributed to the position of the lumbar catheter. The MILP system is an appropriate replacement for temporary catheterization and previous models requiring laminectomy and is a short-term alternative for ventricular CSF collection systems in NHP.

Short Communication: Comparative Evaluation of Coformulated Injectable Combination Antiretroviral Therapy Regimens in Simian Immunodeficiency Virus-Infected Rhesus Macaques.

The use of nonhuman primate (NHP) models to study persistent residual virus and viral eradication strategies in combination antiretroviral therapy (cART)-treated individuals requires regimens that effectively suppress SIV replication to clinically relevant levels in macaques. We developed and evaluated two novel cART regimens in SIVmac239-infected rhesus macaques: (1) a "triple regimen" containing the nucleo(s/t)ide reverse transcriptase inhibitors emtricitabine (FTC) and tenofovir disoproxil fumarate [TDF, prodrug of tenofovir (TFV, PMPA)] with the integrase strand transfer inhibitor dolutegravir (DTG) (n = 3), or (2) a "quad regimen" containing the same three drugs plus the protease inhibitor darunavir (DRV) (n = 3), with each regimen coformulated for convenient administration by a single daily subcutaneous injection. Plasma drug concentrations were consistent across animals within the triple and quad regimen-treated groups, although DTG levels were lower in the quad regimen animals. Time to achieve plasma viral loads stably <30 viral RNA copies/ml ranged from 12 to 20 weeks of treatment between animals, and viral loads <30 viral RNA copies/ml plasma were maintained through 40 weeks of follow-up on cART. Notably, although we show virologic suppression and development of viral resistance in a separate cohort of SIV-infected animals treated with oral DRV monotherapy, the addition of DRV in the quad regimen did not confer an apparent virologic benefit during early treatment, hence the quad regimen-treated animals were switched to the triple regimen after 4 weeks. This coformulated triple cART regimen can be safely, conveniently, and sustainably administered to durably suppress SIV replication to clinically relevant levels in rhesus macaques.

Ventricular Parasystole in a Neonatal Rhesus Macaque (Macaca mulatta).

A 6-d-old Indian-origin female rhesus macaque (Macaca mulatta) presented with bradycardia shortly after sedation with ketamine. No other cardiac abnormalities were apparent. Approximately 2 wk after the initial presentation, the macaque was again bradycardic and exhibited a regularly irregular arrhythmia on a prestudy examination. ECG, echocardiography, blood pressure measurement, SpO2 assessment, and a CBC analysis were performed. The echocardiogram and bloodwork were normal, but the infant was hypotensive at the time of echocardiogram. The ECG revealed ventricular parasystole. Ventricular parasystole is considered a benign arrhythmia caused by an ectopic pacemaker that is insulated from impulses from the sinus node. Given this abnormality, the macaque was transferred to a short-term study protocol, according to veterinary recommendation. On the final veterinary exam, a grade 3 systolic murmur and a decrease in arrhythmia frequency were noted. Gross cardiac lesions were not identified at necropsy the following day. Cardiac tissue sections were essentially normal on microscopic examination. This infant did not display signs of cardiovascular insufficiency, and a review of the medical record indicated normal growth, feed intake and activity levels. This case demonstrates the importance of appropriate screening of potential neonatal and juvenile research candidates for occult cardiovascular abnormalities. Whether the arrhythmia diagnosed in this case was truly innocuous is unclear, given the documented hypotension and the development of a systolic heart murmur.

Elevated Plasma Viral Loads in Romidepsin-Treated Simian Immunodeficiency Virus-Infected Rhesus Macaques on Suppressive Combination Antiretroviral Therapy.

Replication-competent human immunodeficiency virus (HIV) persists in infected people despite suppressive combination antiretroviral therapy (cART), and it represents a major obstacle to HIV functional cure or eradication. We have developed a model of cART-mediated viral suppression in simian human immunodeficiency virus (SIV) mac239-infected Indian rhesus macaques and evaluated the impact of the histone deacetylase inhibitor (HDACi) romidepsin (RMD) on viremia in vivo. Eight macaques virologically suppressed to clinically relevant levels (<30 viral RNA copies/ml of plasma), using a three-class five-drug cART regimen, received multiple intravenous infusions of either RMD (n = 5) or saline (n = 3) starting 31 to 54 weeks after cART initiation. In vivo RMD treatment resulted in significant transient increases in acetylated histone levels in CD4(+) T cells. RMD-treated animals demonstrated plasma viral load measurements for each 2-week treatment cycle that were significantly higher than those in saline control-treated animals during periods of treatment, suggestive of RMD-induced viral reactivation. However, plasma virus rebound was indistinguishable between RMD-treated and control-treated animals for a subset of animals released from cART. These findings suggest that HDACi drugs, such as RMD, can reactivate residual virus in the presence of suppressive antiviral therapy and may be a valuable component of a comprehensive HIV functional cure/eradication strategy.

Development of a cerebrospinal fluid lateral reservoir model in rhesus monkeys (Macaca mulatta).

Rapid, serial, and humane collection of cerebrospinal fluid (CSF) in nonhuman primates (NHP) is an essential element of numerous research studies and is currently accomplished via two different models. The CSF reservoir model (FR) combines a catheter in the 4th ventricle with a flexible silastic reservoir to permit circulating CSF flow. The CSF lateral port model (LP) consists of a lateral ventricular catheter and an IV port that provides static access to CSF and volume restrictions on sample collection. The FR model is associated with an intensive, prolonged recovery and frequent postsurgical hydrocephalus and nonpatency, whereas the LP model is associated with an easier recovery. To maximize the advantages of both systems, we developed the CSF lateral reservoir model (LR), which combines the beneficial features of the 2 previous models but avoids their limitations by using a reservoir for circulating CSF flow combined with catheter placement in the lateral ventricle. Nine adult male rhesus monkeys were utilized in this study. Pre-surgical MRI was performed to determine the coordinates of the lateral ventricle and location of choroid plexus (CP). The coordinates were determined to avoid the CP and major blood vessels. The predetermined coordinates were 100% accurate, according to MRI validation. The LR system functioned successfully in 67% of cases for 221 d, and 44% remain functional at 426 to 510 d postoperatively. Compared with established models, our LR model markedly reduced postoperative complications and recovery time. Development of the LR model was successful in rhesus macaques and is a useful alternative to the FR and LP methods of CSF collection from nonhuman primates.

A novel form of ciliopathy underlies hyperphagia and obesity in Ankrd26 knockout mice.

Human ciliopathies are genetic disorders caused by mutations in genes responsible for the formation and function of primary cilia. Some are associated with hyperphagia and obesity (e.g., Bardet-Biedl Syndrome, Alström Syndrome), but the mechanisms underlying these problems are not fully understood. The human gene ANKRD26 is located on 10p12, a locus that is associated with some forms of hereditary obesity. Previously, we reported that disruption of this gene causes hyperphagia, obesity and gigantism in mice. In the present study, we looked for the mechanisms that induce hyperphagia in the Ankrd26-/- mice and found defects in primary cilia in regions of the central nervous system that control appetite and energy homeostasis.

Effect of suberoylanilide hydroxamic acid (SAHA) administration on the residual virus pool in a model of combination antiretroviral therapy-mediated suppression in SIVmac239-infected indian rhesus macaques.

Nonhuman primate models are needed for evaluations of proposed strategies targeting residual virus that persists in HIV-1-infected individuals receiving suppressive combination antiretroviral therapy (cART). However, relevant nonhuman primate (NHP) models of cART-mediated suppression have proven challenging to develop. We used a novel three-class, six-drug cART regimen to achieve durable 4.0- to 5.5-log reductions in plasma viremia levels and declines in cell-associated viral RNA and DNA in blood and tissues of simian immunodeficiency virus SIVmac239-infected Indian-origin rhesus macaques, then evaluated the impact of treatment with the histone deacetylase inhibitor (HDACi) suberoylanilide hydroxamic acid (SAHA; Vorinostat) on the residual virus pool. Ex vivo SAHA treatment of CD4(+) T cells obtained from cART-suppressed animals increased histone acetylation and viral RNA levels in culture supernatants. cART-suppressed animals each received 84 total doses of oral SAHA. We observed SAHA dose-dependent increases in acetylated histones with evidence for sustained modulation as well as refractoriness following prolonged administration. In vivo virologic activity was demonstrated based on the ratio of viral RNA to viral DNA in peripheral blood mononuclear cells, a presumptive measure of viral transcription, which significantly increased in SAHA-treated animals. However, residual virus was readily detected at the end of treatment, suggesting that SAHA alone may be insufficient for viral eradication in the setting of suppressive cART. The effects observed were similar to emerging data for repeat-dose SAHA treatment of HIV-infected individuals on cART, demonstrating the feasibility, utility, and relevance of NHP models of cART-mediated suppression for in vivo assessments of AIDS virus functional cure/eradication approaches.